Hand-held three-dimensional drawing device

ABSTRACT

A three-dimensional drawing device can include a housing configured for to be held in user&#39;s hand, shaped to allow manipulation of the housing like a pen, and configured to accept a strand of thermoplastic material. The drawing device has a nozzle assembly with an exit nozzle and a motor connected to a gear train that engages the strand such that rotation of the motor causes the feed stock to be extruded out of the exit nozzle to form a three-dimensional object. The motor can be controlled using a variable speed control mechanism or first and second actuators, thereby controlling movement of the strand, for example, to advance or retract the strand relative to the nozzle assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/638,266, filed Jun. 29, 2017, which is a continuation of U.S.application Ser. No. 14/821,399, filed Aug. 7, 2015, which is acontinuation of U.S. application Ser. No. 13/831,050, filed Mar. 14,2013, now U.S. Pat. No. 9,102,098, which claims benefit of and priorityto U.S. Provisional Patent Application Ser. No. 61/733,689, filed onDec. 5, 2012, the entirety of each of which is hereby incorporatedherein by reference.

BACKGROUND Field

The present disclosure relates to extrusion devices and, in particular,a hand-held implement configured to extrude a material so as toconstruct three-dimensional (3D) objects.

Description of the Related Art

Three-dimensional printers are known which may be used to produce 3Ditems of all types. Certain printers operate by deposition of sequentiallayers of plastic while others function by sequential agglomeration orsolidification of layers of a precursor material. These printers tend tobe large and expensive and require the design to be provided as acomputer file, for example as generated by a Computer-Aided Design (CAD)program.

U.S. Pat. No. 3,665,158 to Froedge discloses a conventional handheldextrusion device. A chamber is filled with a granulated solid plasticmaterial and then sealed with a cap. The contents of the chamber areheated to melt the plastic and create pressure within the chamber. Apassage leads from the chamber to a rotatable nozzle that blocks flow ina first position and allows flow in a second position. A trigger isattached to the nozzle such that pulling the trigger moves the nozzle tothe second position, thereby allowing the molten plastic to be expelledfrom the nozzle due to the pressure within the chamber. Releasing thetrigger allows the nozzle to return to the first position, therebystopping the flow of plastic. There is no provision to replenish the rawmaterial without shutting off the device nor any mechanism tomechanically feed material to the nozzle at a constant rate. Inaddition, Froedge's system does not provide a means of cooling theextruded material.

SUMMARY

It is desirable to provide a reliable, easily refillable hand-helddevice to form 2D and 3D items without the need for computerized designfiles. The present disclosure describes a hand-held device that allows auser to “draw” a 3D structure with a feed stock that can be replenishedwhile in continuous use.

In certain embodiments, a 3D drawing device is disclosed that includes ahousing configured for manipulation by a user's hand and to accept afeed stock, a nozzle assembly at least partially disposed within thehousing and having an exit nozzle, a motor disposed within the housing,and a gear train disposed within the housing and coupled between themotor and the feed stock and configured such that rotation of the motorcauses the feed stock to be extruded out of the exit nozzle to form athree-dimensional object.

In certain embodiments, a 3D drawing device is disclosed that includes ahousing configured for manipulation by a user's hand and to accept afeed stock. The housing has an internal volume and at least one coolingport in fluid communication with the internal volume. The 3D drawingdevice also includes a nozzle assembly at least partially disposedwithin the housing proximate to the at least one cooling port and havingan exit nozzle, a fan disposed within the housing and configured to drawair into the internal volume and then force the air out of the at leastone cooling port, a motor disposed within the housing, and an actuatorcoupled to the housing. Actuation of the actuator causes the feed stockto be extruded out of the exit nozzle to form a three-dimensionalobject.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide furtherunderstanding and are incorporated in and constitute a part of thisspecification, illustrate disclosed embodiments and together with thedescription serve to explain the principles of the disclosedembodiments. In the drawings:

FIG. 1 is a perspective view of an exemplary 3D drawing device accordingto certain aspects of the present disclosure.

FIG. 2 is a cut-way view of the device of FIG. 1 with a portion of thehousing removed according to certain aspects of the present disclosure.

FIGS. 3A-3B are cross-sectional and cutaway views of the device of FIG.1 according to certain aspects of the present disclosure.

FIGS. 4A-4B are plan and perspective views of the feed mechanismaccording to certain aspects of the present disclosure.

FIGS. 5A-5B are perspective and cutaway views of another embodiment of a3D drawing device according to certain aspects of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure describes a hand-held device that allows a userto “draw” a 2D or 3D structure and to easily refill or replace the feedstock.

The detailed description set forth below is intended as a description ofvarious configurations of the subject technology and is not intended torepresent the only configurations in which the subject technology may bepracticed. The appended drawings are incorporated herein and constitutea part of the detailed description. The detailed description includesspecific details for the purpose of providing a thorough understandingof the subject technology. However, it will be apparent to those skilledin the art that the subject technology may be practiced without thesespecific details. In some instances, well-known structures andcomponents are shown in block diagram form in order to avoid obscuringthe concepts of the subject technology. Like components are labeled withidentical element numbers for ease of understanding.

As used within this disclosure, the phrase “feed stock” means anymaterial provided in any form suitable for processing within the 3Ddrawing device so as to provide the desired output stream. Feed stockmay be a thermoplastic such as acrylonitrile butadiene styrene (ABS),polyvinyl chloride (PVC) or a polylactic acid (PLA), a thermosetmaterial such as an epoxy, a metal such as tin or lead or a mixture ofmetals. Feed stock may be a single material or a mixture of materials,such as a rod having particles of a first material dispersed within amatrix of a second material.

FIG. 1 is a perspective view of an exemplary 3D drawing device 100according to certain aspects of the present disclosure. The device 100includes a housing 110 in which a control assembly 120, a nozzleassembly 130, a fan assembly 140 are provided. The housing 110 may besized and configured to fit in a user's hand and suitably shaped toallow for manipulation like a pen or pencil. An actuator, for examplebuttons 122 and 124 in this embodiment, may be positioned to allow theuser to actuate either the actuator while holding the device 100. Inthis embodiment, the user may actuate one or both of buttons 122, 124while manipulating the 3D drawing device 100. In this embodiment, thedevice 100 is configured to accept a feed stock 20 in the form of astrand that may be 3 mm in diameter. In certain embodiments, the feedstock 20 may be provided as a cut length, for example 30 cm in length,or as a continuous strand drawn from a spool (not shown in FIG. 1). Thedevice 100 includes an input port 115, or other input element, such as ahopper, for example, through which a raw material is provided to thedevice 100. The feed stock 20 may be a thermoplastic material, forexample a PVC, an ABS, or a PLA, however, other embodiments may acceptother types of material, such as a thermoset plastic or a metal orcombination of materials.

In an example of use of one embodiment of the device 100, the userselects a particular type and color of a thermoplastic feed stock 20 andintroduces the feed stock 20 into the entrance port 115 (see FIG. 2) andconnects a power cord (not shown in FIG. 1) to a power source, such as awall outlet. In certain embodiments, the 3D drawing device 100 mayinclude a portable power source (not shown in FIGS. 1-2), for example alithium polymer battery, to power the device 100. After a warm-upperiod, the user may press button 122 while drawing a line on a surfacewith the device 100, for example tracing a pattern on a printed sheet,in a manner similar to drawing a line with a pencil. A column 22 of thefeed stock 20 is extruded from the nozzle assembly while the button 122is depressed. In certain embodiments, the column 22 may be 0.3 mm indiameter. If the user moves the device along the surface atapproximately the same speed as the rate of extrusion of the column 22,the user will create a solid, three-dimensional “line” on the surface.In certain embodiments, the feed stock 20 exits the nozzle assembly 130in essentially a solid form such that the extruded column retains itsshape. In certain embodiments, freshly extruded feed stock 20 will bondto previously extruded columns 22 such that a structure may be formed bydrawing a line across to a previously drawn column 22.

In certain embodiments, button 122 may cause the feed stock 20 to beextruded at a first rate, for example 2.6 mm/sec, while the secondbutton 124 may cause the feed stock 20 to be extruded at a second rate,for example 5.0 mm/sec. In certain embodiments, the first rate may be inthe range of 0.1-10.0 mm/sec and the second rate may be in the range of2-50 mm/sec. In certain embodiments, the first and second rates arechosen to provide a speed appropriate for the intended user, for examplea device 100 intended for use by a young child may have slower ratesthan a device 100 intended for an adult artist. In certain embodiments,the 3D drawing device 100 may include a variable speed control mechanism(not shown in FIG. 1-2) to allow the user to adjust one or more of therates of extrusion. In certain embodiments, the variable speed controlmechanism may include a dial. In certain embodiments, releasing eitherof the buttons 122, 124 may cause the internal mechanism to draw thefeed stock 20 backward a certain amount, thereby breaking off theextruded column 22. In this manner, the user can “write” with the 3Ddrawing device 100 in much the same manner as they would with a penexcept they can do so in three dimensions since the extruded material isthree-dimensional. The user can create free-form lines, shapes or otherobjects, as desired. A user may additionally use stencils or otherguides in order to create desired objects such as sculpture, jewelry,artistic pieces, etc. In addition, or in the alternative, the 3D drawingdevice 100 may be used to repair or enhance existing objects andstructures. In certain embodiments, pressing both buttons 122, 124 atthe same time may cause another action, such as expelling the unusedportion of the feed stock 20 from the entrance port 115 such that theuser may switch to a different color or type of feed stock 20.

FIG. 2 is a cut-way view of the device 100 of FIG. 1 with a portion ofthe housing 110 removed according to certain aspects of the presentdisclosure. It can be seen that a circuit assembly 126 is positionedunder the switches 122, 124 and a feed mechanism 150 is disposed on thelower housing 114, with the feed stock 20 entering through the entranceport 115 and passing over and between elements of the feed mechanism150, which is discussed in greater detail with respect to FIGS. 4A-4B.In certain embodiments, the circuit assembly 126 may include a processorwhile, in certain embodiments, the circuit assembly 126 may includeanalog circuit elements such as mechanical switches, resistors,capacitors, and other electrical elements (not visible in FIG. 2) asknown to those of skill in the art. In certain embodiments, the circuitassembly 126 may include a power conditioning circuit (not shown) thatconverts power from the power source to a different form, such as adirect current (DC) voltage. In certain embodiments, the circuitassembly 126 may include a portable power source (not shown in FIG. 2).In certain embodiments, the circuit assembly 126 may be connected to anexternal power source through a power cord (not shown in FIGS. 1-2). Incertain embodiments, the 3D drawing device 100 also includes an externalcontrol interface 127 that is connected to the circuit assembly 126 andconfigured to accept actuation commands from a remote system, such as acomputer numerical control (CNC) machine. In certain embodiments, thehousing 110 may be adapted for mounting on a tool interface of a CNCmachine such that the machine can manipulate the 3D drawing device 100to create 3D objects. For example, the external control interface 127may include three electrical pins, wherein a pin 1 is a common such as aground, a pin 2 that is coupled to the button 122 such that provision ofa DC voltage across pin 1 and pin 2 is equivalent to pressing button122, and a pin 3 that is coupled to the button 124 such that provisionof a DC voltage across pin 1 and pin 3 is equivalent to pressing button124. In certain embodiments, the external control interface 127 may beconfigured to accept signals through a radio frequency (RF) or opticalwireless system. In certain embodiments, the external control interface127 may be configured to accept signals through a fiber-optic cable.

FIGS. 3A-3B are cross-sectional and cutaway views of the device 100 ofFIG. 1 according to certain aspects of the present disclosure. FIG. 3Ais a side view of the entire 3D drawing device 100, showing how theupper housing 112 and lower housing 114 together form an internal volume116 in which is located the feed mechanism 150. At the right end, it canbe seen that the nozzle assembly 130 includes an extruder 132 and aguide tube 134, which are discussed in greater detail with respect toFIG. 3B. the fan assembly 140 includes a fan cover 142, which isstationary and attached to the upper housing 112, an impeller 14 locatedunderneath the cover 142 and configured to draw air into the internalvolume 116 through ports (not visible in FIG. 3A) in the cover 142. Amotor 146 is mounted, in this example, to the lower housing 114 anddrives the impeller 144 at a constant speed. The air that is drawn intothe internal volume may, in certain embodiments, flow out through eithercooling ports 118 in the upper and lower housings 112, 114. The coolingports 118 are discussed in greater detail with respect to FIG. 3B. Itcan be seen in FIG. 3A that, in this embodiment, the feed stock 20follows a straight path though the device 100.

FIG. 3B is a close-up, cutaway view of the nozzle assembly 130. Theextruder 132 has a first chamber 135 formed as a cylindrical bore ofapproximately the same diameter as the feed stock 20 and an extrusionpassage 133 of a smaller diameter, terminating in an exit nozzle 133A.In certain embodiments, the first chamber 135 may have a first diameterof 3 mm while the extrusion passage 133 has a diameter of 0.3 mm. Incertain embodiments, the extruder 132 is formed of a thermallyconductive material, for example a metal or a ceramic, with a heatingelement, for example a nichrome wire, (not visible in FIG. 3B) woundaround the exterior circumference. When the device 100 is connected to apower source, the heating element raises the temperature of the extruder132 to a temperature that may be above the melting point of the feedstock 20. In certain embodiments, the nozzle assembly 130 includes atemperature sensor that is connected to the circuit assembly 126 whichmay include a temperature control circuit to regulate the power to theheater element so as to maintain the temperature of the extruder 132within a desired range of a setpoint. As systems and methods fortemperature regulation are known to those of skill in the art, thedetails are not provided herein. In certain embodiments, an indicator(not shown), for example an LED, may be provided to indicate that theextruder 132 has reached a temperature sufficient to melt the feed stock20.

In certain embodiments, for example with a feed stock comprising aplastic, the temperature of the extruder 132 may be in the range of20-500° C. In certain embodiments, for example with a feed stockcomprising a metal, the temperature of the extruder 132 may be in therange of 1000-2000° C. In certain embodiments, for example with a feedstock comprising a metal such as lead, tin, or mixtures thereof, thetemperature of the extruder 132 may be in the range of 100-400° C. Incertain embodiments, for example with a feed stock comprising a metalsuch as copper, gold, silver or mixtures thereof, the temperature of theextruder 132 may be in the range of 1000-1200° C. In certainembodiments, for example with a feed stock comprising a metal such asplatinum, the temperature of the extruder 132 may be in the range of1600-2000° C. In certain embodiments, the 3D drawing device 100 mayinclude a variable temperature controller (not shown) that is connectedto the circuit assembly 126 to allow a user to select a setpointtemperature for the extruder 132. In certain embodiments, the variabletemperature controller may allow the use to select a type of material,for example “thermoplastic,” and the circuit assembly 126 will adjustthe setpoint temperature of the extruder 132. In certain embodiments,the variable temperature controller may include a dial.

A guide tube 134 is aligned with the first chamber 135 of the extruder132 such that feed stock passing through the guide tube 134 enters thefirst chamber 135. In certain embodiments, the guide tube 134 may beformed of a low-friction material, such as polytetrafluoroethylene(PTFE), so allow the feed stock 20 to slide easily while also minimizingthe gap between the guide tube 134 and feed stock 20. The extruder 132and guide tube 134 are held in alignment by a mounting tube 138. Incertain embodiments, the mounting tube 138 is formed of a metal having arelatively low thermal conductivity, compared to other metals. Incertain embodiments, the mounting tube 138 may be a stainless steel. Incertain embodiments, an insulating film (not visible in FIG. 3B), forexample a polyimide tape, may be applied over the heating element andunder the mounting tube 138.

In certain embodiments, an insulator 131 may be provided over themounting tube 138 so as to reduce the amount of heat transferred fromthe extruder 132 to the upper and lower housings 112, 114. In certainembodiments, one or both of the upper and lower housings 112, 114 mayhave cooling ports 118 formed therethrough such that air can flow fromthe interior volume 116 to the ambient atmosphere. In certainembodiments, the passages formed in the top and bottom housings 112, 114that lead to the cooling ports 118 may be angled such that the air thatemerges from the cooling ports 118 is directed inward toward the tip137. Thus, as the air exits the cooling ports 118, the air passes by thetip 137 of the extruder 132, cooling both the tip 137 and the feed stock20 that just been extruded from the extrusion passage 133. Both of thesecooling effects serve to reduce the temperature of the feed stock 20 asit exits the extrusion passage 133 such that the feed stock 20 may beessentially solid as it exits the extrusion passage 133. In certainembodiments, the freshly extruded feed stock 20 may be pliable andformable into various shapes. In certain embodiments, the surface of thefreshly extruded feed stock 20 may be receptive to attachment, e.g.sticky, such that the extruded material will bond to other previouslyextruded feed stock 20.

In certain embodiments, there may be a gap between the insulator 131 andthe mounting tube 138. In certain embodiments, this gap may provide athermal break so as to further thermally isolate the upper and lowerhousings 112, 114 from the extruder 132.

As the feed stock 20 is driven toward the extrusion passage 133 by thefeed mechanism 150 (not shown in FIG. 3B), the portion of the feed stock20 that is within the extruder 132 will be heated by the extruder 132such that the feed stock 20 within the first chamber 135 softens ormelts. As the solid feed stock 20 is forced forward, the softened ormolten feed stock 20 will be forced out through the extrusion passage133 and emerge from the tip 137, where the cooling air that is flowingout of the cooling ports 118 flows over the freshly extruded feed stock20, thereby cooling and solidifying the feed stock 20. In certainembodiments, a portion of the extruder 132 that extends outward beyond afront plane 102 may be cooled to a temperature below the temperature ofthe main portion of the extruder 132 by the air flowing out of thecooling ports 118. In certain embodiments, the temperature of the tip137 may be below the melting point of the feed stock 20.

FIGS. 4A-4B are plan and perspective views of the feed mechanism 150according to certain aspects of the present disclosure. FIG. 4A shows aseries of gear pairs 153, 154, 155, 156, and 157 that are driven by themotor 152 through a spur gear (not visible in FIG. 4A) that is attachedto the rotor of the motor 152. Each gear pair has a large gear and asmall gear that are fixedly attached to each other and rotate about acommon axis. The small gear of the motor 152 drives the large gear 153A,which causes the small gear 153B to drive the large gear 154A. Incertain embodiments, the large gears 153A, 154A, 155A, 156A, and 157Aeach may have 40 teeth while the small gears 153B, 154B, 155B and 156B(not visible in FIG. 4A), and 157B may have 12 teeth, providing a 40:12step-down ratio between each gear pair. In certain embodiments, thestep-down from the motor 152 to the small gear 157B may be 5*(40:12) orapproximately 17:1, i.e. seventeen complete rotations of the motor 152causes only one complete rotation of the small gear 157B. In certainembodiments, the gear pairs 153, 154, 155, 156, and 157 may have adifferent number of teeth on the large and/or small gears. In certainembodiments, the gear pairs 153, 154, 155, 156, and 157 may not have thesame number of teeth on each corresponding large or small gear.

In use, the use of a motor 152 to drive a step-down gear train 150 tocontrol the advancement of the feed stock 20 provides an improved levelof control over the rate of extrusion of the feed stock 20. For example,a conventional glue gun has a direct linkage between a trigger and theglue stick, such that pressure on the trigger on the trigger is directlytransferred to the rod. The rate of advancement of the glue stick, andtherefore the rate of extrusion, is dependent upon the viscosity of themelted glue and therefore caries over a die range. This often results inexcessive glue being dispensed. In addition, since releasing the triggerdoes not retract the glue stick, there is frequently a “tail” of gluedrawn out of the glue gun as the nozzle is moved away from thedispensing location. In contrast, the disclosed 3D drawing device 100provides a constant rate of extrusion, for example 3 mm/sec, due to thecontrolled motion provided by the motor 152 and gear train 150. Inaddition, the circuit assembly 126 causes the motor 152 to briefly runin reverse when the button 122 is released, thereby retracting the feedstock 20 slightly and drawing the melted feed stock 20 that is withinthe extrusion passage 133 back into the extruder 132, thereby cleanlysevering the extruded column 22 from the tip 137.

FIG. 4B shows how the teeth of the final small gear 157B engage the feedstock 20. In this embodiment, the feed stock 20 passes by a post 119 ofthe lower housing 114, then by the small gear 157B, and then into theguide tube 134. In certain embodiments, the gear 157B is positioned suchthat the teeth press against the feed stock 20, which is restrained fromlateral motion away from the teeth of gear 157B by the post 119 and theguide tube 134, such that rotation of the gear 157B applies an axialforce, i.e. directed along the length, to the feed stock 20. Rotation ofthe gear set 150 in a first direction will cause the feed stock 20 tomove linearly forward, i.e. toward the tip 137. As this portion of feedstock 20 is not affected by the heating within the extruder 132,rotation of the gear set 150 in a reverse direction will cause the feedstock 20 to move linearly backward, i.e. away from the tip 137.

It can be seen from FIGS. 4A and 4B that rotation of the motor 152,which is controlled by pressing one of the buttons 122, 124, causes thefeed stock 20 to move forward or backward. The step-down from the motor152 to the small gear 157B provides a smooth rate of motion of the feedstock, as the motor 152 may turn at a speed within a normal range ofsmooth operation while the step-down converts this to a low rate oflinear motion of the feed stock 20.

FIGS. 5A-5B are perspective and cutaway views of another embodiment 200of a 3D drawing device according to certain aspects of the presentdisclosure. FIG. 5A shows a 3D drawing device 200 configured to accept afeed stock in the form of pellets 25 that are held in a hopper 250attached to the body 210. A power cord 270 is attached to the body 210.FIG. 5B is a cut-away view showing a feed screw 260 that transfers thepellets 25 from the hopper 250 to the nozzle assembly 230 that melts thepellets 25 and, under pressure provided by the feed screw 260, extrudesthe melted feed stock 25 in a manner similar to the nozzle assembly 130of embodiment 100, previously discussed. Other features of theembodiment 100, such as the cooling ports 118, may also be provided inembodiment 200. In certain embodiments, the pellets may be transferredfrom the hopper 250 to the nozzle assembly 130 by other mechanisms, forexample a reciprocating cylinder (not shown in FIGS. 5A-5B) as will beknown to those of skill in the art. In certain embodiments, the feedstock may be provided as a liquid, for example an epoxy with beads ofcatalyst suspended in a liquid polymer, that is held in the hopper 250.In certain embodiments, passage of the liquid feed stock through anextrusion passage, similar to extrusion passage 133 of embodiment 100,may modify the liquid feed stock such that it hardens quickly afterextrusion from the 3D drawing device 200.

The disclosed examples of a 3D drawing device illustrate the principlesof its construction and use. The provision of a flow of cooling air atthe tip to quickly solidify the extruded feed stock allows the user towork in three dimensions, rather than being forced to rely on a supportsurface to hold the still-fluid extruded material in place while ithardens. The use of a mechanical gear train to advance the feed stock,instead of a pressurized supply or a direct connection between a triggerand a feed rod, allows precise control of the rate of extrusion, therebyincreasing the uniformity of the extruded column of material andallowing precise placement without excess material.

This application includes description that is provided to enable aperson of ordinary skill in the art to practice the various aspectsdescribed herein. While the foregoing has described what are consideredto be the best mode and/or other examples, it is understood that variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. It is understood that the specific order or hierarchy ofsteps or blocks in the processes disclosed is an illustration ofexemplary approaches. Based upon design preferences, it is understoodthat the specific order or hierarchy of steps or blocks in the processesmay be rearranged. The accompanying method claims present elements ofthe various steps in a sample order, and are not meant to be limited tothe specific order or hierarchy presented. Thus, the claims are notintended to be limited to the aspects shown herein, but is to beaccorded the full scope consistent with the language claims.

Headings and subheadings, if any, are used for convenience only and donot limit the invention.

Reference to an element in the singular is not intended to mean “one andonly one” unless specifically so stated, but rather “one or more.” Useof the articles “a” and “an” is to be interpreted as equivalent to thephrase “at least one.” Unless specifically stated otherwise, the terms“a set” and “some” refer to one or more.

Terms such as “top,” “bottom,” “upper,” “lower,” “left,” “right,”“front,” “rear” and the like as used in this disclosure should beunderstood as referring to an arbitrary frame of reference, rather thanto the ordinary gravitational frame of reference. Thus, a top surface, abottom surface, a front surface, and a rear surface may extend upwardly,downwardly, diagonally, or horizontally in a gravitational frame ofreference.

Although the relationships among various components are described hereinand/or are illustrated as being orthogonal or perpendicular, thosecomponents can be arranged in other configurations in some embodiments.For example, the angles formed between the referenced components can begreater or less than 90 degrees in some embodiments.

Although various components are illustrated as being flat and/orstraight, those components can have other configurations, such as curvedor tapered for example, in some embodiments.

Pronouns in the masculine (e.g., his) include the feminine and neutergender (e.g., her and its) and vice versa. All structural and functionalequivalents to the elements of the various aspects described throughoutthis disclosure that are known or later come to be known to those ofordinary skill in the art are expressly incorporated herein by referenceand are intended to be encompassed by the claims. Moreover, nothingdisclosed herein is intended to be dedicated to the public regardless ofwhether such disclosure is explicitly recited in the claims. No claimelement is to be construed under the provisions of 35 U.S.C. § 112,sixth paragraph, unless the element is expressly recited using thephrase “means for” or, in the case of a method claim, the element isrecited using the phrase “operation for.”

A phrase such as an “aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations. Aphrase such as an aspect may refer to one or more aspects and viceversa. A phrase such as an “embodiment” does not imply that suchembodiment is essential to the subject technology or that suchembodiment applies to all configurations of the subject technology. Adisclosure relating to an embodiment may apply to all embodiments, orone or more embodiments. A phrase such as an embodiment may refer to oneor more embodiments and vice versa.

The word “exemplary” is used herein to mean “serving as an example orillustration.” Any aspect or design described herein as “exemplary” isnot necessarily to be construed as preferred or advantageous over otheraspects or designs.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.” Furthermore, to the extent that the term “include,” “have,” or thelike is used in the description or the claims, such term is intended tobe inclusive in a manner similar to the term “comprise” as “comprise” isinterpreted when employed as a transitional word in a claim.

Although embodiments of the present disclosure have been described andillustrated in detail, it is to be clearly understood that the same isby way of illustration and example only and is not to be taken by way oflimitation, the scope of the present invention being limited only by theterms of the appended claims.

What is claimed is:
 1. An apparatus comprising: a three-dimensional (3D)drawing pen that is configured to permit drawing in 3D space, theconfiguration of the pen comprising: an elongate housing having aninternal volume and a port that permits insertion of a strand ofmaterial into the internal volume of the pen, the elongate housing beingconfigured to fit in a user's hand and shaped to allow manipulation ofthe pen without a handle substantially perpendicular to the housing; arotatable gear disposed within the internal volume of the housing of thepen, the gear being configured to contact the strand when engaged withthe gear within the housing of the pen; a motor, disposed within theinternal volume of the housing of the pen, operatively coupled with thegear and configured to rotate the gear and drive motion of the strand;an actuator, positioned along the housing of the pen, to actuate themotor to control a movement of the strand; and a nozzle assemblydisposed at a distal end of the pen and comprising an extruder and anexit nozzle, the extruder having a heating element configured to meltthe strand, the extruder being disposed between the gear and the exitnozzle such that the strand can be driven into and melted by theextruder to cause the strand to be extruded out of the exit nozzle in asolid form that retains its shape against gravity in free space to drawa 3D object.
 2. The apparatus of claim 1, wherein the gear is disposedadjacent to the port within the internal volume.
 3. The apparatus ofclaim 1, further comprising a mounting tube having a first end and asecond end, and wherein a second end of a guide tube extends into thefirst end of the mounting tube, and an end of the extruder opposite thenozzle extends into the second end of the mounting tube, the mountingtube holding the second end of the guide tube in alignment with the endof the extruder opposite the nozzle.
 4. The apparatus of claim 1,wherein the housing comprises an upper housing and a lower housing, atleast one of the upper housing and the lower housing comprising acooling port proximate to the nozzle.
 5. The apparatus of claim 1,further comprising a variable speed control mechanism operativelyconnected to the motor to adjust one or more of a first extrusion rateand a second extrusion rate.
 6. The apparatus of claim 1, wherein theheating element is positioned adjacent to the exit nozzle and configuredto melt the strand of material prior to extrusion through the exitnozzle.
 7. The apparatus of claim 1, wherein the housing comprises atleast one cooling port proximate to the exit nozzle, the cooling port influid communication with the internal volume.
 8. The apparatus of claim1, wherein the gear comprises a final gear having teeth that engage thestrand of material such that rotation of the final gear causes thestrand of material to linearly move.
 9. The apparatus of claim 1,further comprising a fan configured to provide a flow of cooling airtoward the exit nozzle.
 10. The apparatus of claim 1, wherein thehousing comprises a length between a first end and a second end, thelength being greater than a maximum transverse extent of the housing.11. The apparatus of claim 1, wherein the pen is configured to extrudethe strand out of the exit nozzle in a continuous, vertical form.
 12. Athree-dimensional (3D) drawing pen comprising: an elongate housinghaving an internal volume and a port that permits insertion of a strandof material into the internal volume, the elongate housing beingconfigured to fit in a user's hand and shaped to allow manipulation ofthe pen to permit drawing 3D objects in free space; a drive systemcomprising a gear and a motor disposed within the internal volume, thegear being operatively coupled with the motor to drive motion of thestrand of material when inserted through the port and engaged with thegear; at least one actuator, positioned along the housing of the pen,for controlling a movement of the strand; and a nozzle assembly disposedat a distal end of the housing and comprising an extruder and an exitnozzle, the extruder having a heating element for melting the strand,the extruder being disposed between the gear and the exit nozzle suchthat the strand can be driven into and melted by the extruder to causethe strand to be extruded out of the exit nozzle in a solid, continuousform that retains its shape against gravity in free space to draw a 3Dobject.
 13. The 3D drawing pen of claim 12, further comprising a guidetube disposed within the housing and extending between the gear and theextruder, a first end of the guide tube positioned to receive the strandfrom the gear, a second end of the guide tube aligned with a chamber ofthe extruder such that the strand is directed into the chamber.
 14. The3D drawing pen of claim 12, wherein the housing comprises at least onecooling port extending between the internal volume and an ambientatmosphere.
 15. The 3D drawing pen of claim 12, wherein the gear isdisposed adjacent to the port within the internal volume.
 16. The 3Ddrawing pen of claim 12, further comprising a mounting tube having afirst end and a second end, and wherein a second end of a guide tubeextends into the first end of the mounting tube, and an end of theextruder opposite the nozzle extends into the second end of the mountingtube, the mounting tube holding the second end of the guide tube inalignment with the end of the extruder opposite the nozzle.
 17. The 3Ddrawing pen of claim 12, wherein the housing comprises an upper housingand a lower housing, at least one of the upper housing and the lowerhousing comprising a cooling port proximate to the nozzle.
 18. The 3Ddrawing pen of claim 12, wherein comprising a variable speed controlmechanism operatively connected to the motor to adjust one or more of afirst extrusion rate and a second extrusion rate.
 19. The 3D drawing penof claim 12, wherein comprising a fan configured to provide a flow ofcooling air toward the exit nozzle.
 20. The 3D drawing pen of claim 12,wherein the housing comprises a length between a first end and a secondend, the length being greater than a maximum transverse extent of thehousing.